Compensating device for thread feed spools



July 17, 1962 H. SCHIPPERS COMPENSATING DEVICE FOR THREAD FEED SPOOLS 4 Sheets-Sheet 1 Filed NOV. 15, 1960 4...; (KHZ ATT'YS July 17, 1962 H. SCHIPPERS 3,044,246

COMPENSATING DEVICE FOR THREAD FEED SPOOLS INVENTOR: HEINZ SCHIPPERS y 1962 H. SCHIPPERS 3,044,246

COMPENSATING DEVICE FOR THREAD FEED SPOOLS Filed Nov. 15, 1960 I 4 Sheets-Sheet 3 INVENTOR: HEINZ SCHIPPERS ATT'YS July 17, 1962 H. SCHIPPERS 3,044,246

COMPENSATING DEVICE FOR THREAD FEED SPOOLS Filed Nov. 15, 1960 4 Sheets-Sheet 4 INVENTOR. HEINZ SCHIPPERS we W5;

ATT'YS United States 3,044,246 COMPENSATING DEVICE FOR THREAD FEED SPOOLS This invention relates to an improved device for compensating the rate at which thread is drawn oif from a plurality of bobbins, and in particular, to an improved compensating device for drawing ofi equal lengths of thread from bobbins or feed spools which rotate independently on the same axis or on separate axes. The invention is especially useful in combination with textile apparatus of the type known as a double twist twisting machine, sometimes referred to as a multiple twist or a two-for-one twisting machine.

Where two or more threads are to be twisted together, it has been a common practice to draw the threads from a single bobbin or feed spool and feed them into the twisting device. In this process, e.g. in the twisting of two threads on a double twist twisting machine, it is essential that the threads first be wound upon the single feed spool with as equal and uniform a tension as possible. This preliminary winding step is both time consuming and difficult to achieve, especially in the commercial handling of a large volume of thread.

In order to avoid the preliminary operating step, it was thought that it might be possible to employ two or more feed spools of the so-called discus or solar type from which the threads would be drawn oii individually and then brought together prior to twisting. However, unless there is some means of compensating for the variable rate at which the individual feed spools rotate, unequal lengths of thread are unwound during the process and there is an undesirable formation of slack threads and ribby or knotted yarn after twisting. Thus, some means must be provided to prevent one of the threadwound spools or bobbins from running ahead or lagging behind the other.

One device adapted to provide this compensation and synchronize the rotation of the feed spools is disclosed in copending application, Serial No. 859,943, filed December 16, 1959, the subject matter of which is incorporated herein by reference as fully as if it were set forth in its entirety. As disclosed, this device essentially includes a friction roller for each of two bobbins, the rollers being mounted on a common yoke and urged resiliently for rolling contact against the outer circumference of the bobbins. The rollers are interconnected by being solidly joined for rotation on a common axle and thus are caused to rotate at the same rate of revolution. The rotational velocity of the feed spools or bobbins is also synchronized because if one bobbintends to run ahead, the other bobbin acts with a braking effect through the frictional force of the roller which links the two bobbins.

In the present invention, there are provided improved compensating means which operate on substantially the same principle. In addition, the device .of the present invention permits a greater flexibility in operation and a wider application of the compensating principle to various arrangements of two or more feed spools or bobbins.

A principal object of the invention is to provide an improved compensating device to adjust and synchronize the rate at which threads are drawn from a multiple number of feed spools or bobbins.

A particular object of the invention is to provide an improved compensating device which can be used with bobbins which are adjacently mountedfor normally inatent dependent rotation on the same axis or on different axes which may be parallel to or at an angle with each other.

Another object of the invention is to provide a compensating device which can be readily adapted to bobbins of different diameter or spools which are wound with threads of difiering sizes or textures.

Still another object is to provide a compensating device which can be readily adapted to bobbins rotating in opposite directions on the same axis or on diiferentaxes.

Yet another object of the invention is'to provide an improved apparatus for drawing equal lengths of thread from a series of two or more bobbins, as in double twist twisting machines or in other apparatus where it is essential to prevent the formation of unequal thread lengths.

These and other objects and advantages of the in'- vention will be more clearly understood when considered together with the following detailed description and with the accompanying drawings in which the same numerals are employed to designate similar parts in the various figures.

In the drawings:

FIG. 1 is a side elevational and partly schematic view of a double twist twisting machine in combination with the improved compensatingapparatus of the invention;

FIG. 2 is a side elevational view corresponding to FIG. 1 with portions omitted and illustrating a slightly difierent embodiment of belt guide means of the compensating ppar FIG. 3 is a perspective view of the elements corresponding to the particular belt guide means of FIG. 2;

FIG. 4 is a perspective view of the elements corresponding to the particular belt guide means of FIG. 1;

FIG. 5 is a partial side elevational view of a single bobbin, its compensating element and belt, illustrating another specific embodiment of the invention;

FIG. 6 is a side elevational view of still another em,- bodiment of the invention illustrating a diiferent method of mounting friction rollers on individually adjustable carrier arms;

FIG. 7 is a side elevational view illustrating the manher in which the invention can be adapted to three independently rotating bobbins;

:FIG. 8 is a side elevational view of still another variation of the apparatus shown in FIG. 1;

FIG. 9 is a side elevational view corresponding to FIG. =1 and illustrating the location of a gear box adapted to provide a positive drive to afriction roller;

-FIG. 10 is an enlarged view of a portion of the yokeshaped carrying arms of FIG. 1, illustrating a suitable swivel joint;

FIG. 1 is a front elevational view, partly in schematic form, of still another embodiment of the inventionwhere in the compensating apparatus is employed with bobbins mounted rotatably on independent, non-parallel spin dles;

FIG. 12 is an enlarged front elevational view of the adjustablebelt guide means disclosed in FIG. 11;

FIG. 13 is a top plan view taken from FIG. 12;

FIG. 14 is a front elevational View, partly in schematic form, of yet another" embodiment of the invention wherein the compensating apparatus is employed with bobbins mounted rotatably on independent, parallel spindles;

FIG. I5 is a top plan view taken from FIG. 14; and

FIG. 16 is an enlarged, partial perspective view of one of the friction rollers shown in' FIG. 1, except that the belt guide means is adjustably mounted.

InFI'GS. l-lO, the compensating apparatus of the invention is shown in combination with a typical twisting machine, and it will be understood that various conven-' tional portions have been omitted in FIGS. 2-9 where such portions are identical to FIG. I. FIGS. ll -l3 are" set forth to illustrate the adaptability of the invention to:

' 3 I other types of apparatus having two or more bobbins. In every case, the axis of each bobbin can be in a vertical position or in any inclined position down to and includ-' ing a horizontal position. 1 In accordance with the invention, an improved compen- 's'ating device is provided by apparatus essentially including spindle means for mounting a plurality of bobbins such that said bobbins will normally rotate independently of one another, one or more friction rollers for each bobbin with the axis of each roller being approximately parallel to the axis of its associated bobbin, means to urge each of the friction rollersresiliently inwardly in approximately tangential position against the outercircumferential surface of its respective bobbin, and torque transmitting means including a belt drive extending between and operatively coupling a pair of said friction rollers where each roller of 'the'pair'is associated with a difierent bobbin. All of the foregoing essential elements are mounted or connected directly or indirectly to a stationary framework in the form of a housing,'floor mounted stands or any similar structure. The friction rollers are mounted indijvidually for normally independent rotation and are operatively coupled only by the torque transmitting means according to the invention. The friction roller may rest directly on the outer circumferential surface of its associated bobbin, or, else a separate surface such as the driving-belt itself is located around the circumference of the roller to engagethe' outer surface of the bobbin in frictional rollingcontact. 2 The torque transmitting means of the invention is pref- 'erably a belt drive, is. an endless belt which is held in tension between a pair of rollers and is engaged with each roller itself or a drive shaft on each roller such' that the rotational speed of one roller is made approximately equal to'the rotational speed of the other roller. It is also feasibleto provide each roller shaft with a tooth wheel gear which in turn engages and drives a second gear with a belt drive or shaft drive connecting the second gear of a pair of rollers. Other equivalent torque transmitting incans such as a' flexible cable or pure. gear drive between pairs of rollers will be readily apparent to those skilled in the art, but for the purposes of the invention a belt These carrier arms arepivotally mounted to swing the ifoller inwardly againstthe bobbin by means of a resilient spring or the like. In addition, these swinging carrier arms.

the bobbins, it is advisable to maintain or hold the rollers out of contact with the bobbins when the threads are initially drawn off and the bobbin speed increases from a standstill to the desired rotational velocity. A further embodiment of the invention includes a separate drive means connected .to one of the coupled rollers for starting the rollers from a standstill and thereby overcoming initial inertia or frictional drag. In this case, the rollers can remain in contact or engagement at all times with the coupled bobbins. V

V The apparatus of the invention is particularly useful to provide a compensation in the operation of a double twist twisting machine. However, the same apparatus can be modified for use with ring-twisting machines or similar devices. Thus, two or more bobbins can be mounted on a single vertical axis or separate adjacent parallel axes, and a pair of coupled friction rollers linking each adjacent bobbin in a series. A pair of coupled rollers may also act on the first and last of a series of three or more bobbins, and in fact, it is possible though seldom necessary to have one pair of friction rollers for every possible combination of two bobbins.

The outer cylindrical surface of the friction rollers can be smooth but may also beroughened or given a grooved or cross-hatched texture to provide a smaller or greater coefficient of friction. Such variation is often helpful Where threads of slightly dilferent texture are twisted together. The power transmission capacity of the rollers is in general dependent upon this coefiicient of friction and the contact pressure under which the rollers are urged against the bobbins. By coupling each bobbin to at least one additional bobbin of a series, the torque applied by one bobbin is proportionately distributed over the remaining rollers. The coefficient of friction can also be adjusted by varying the force with which the roller is urged inwardly against its bobbin as noted above. In particular cases, some experimentation may be required to obtain a perfect coupling, and the provision of an adjustable urging means, belt tensioning-rneans and the like makes this procedure a package which is unwound or drawn off in the usual fashpreferably have attached thereto in adjustable position a rod or rollerguide means adapted to direct the path of the driving belt and to place an adjustabletension onthe belt. 'Suchbelt guide means may alsobe mounted independently of the carrier arms in a relatively fixed guide path between a pair of rollers.

H The bobbins during operation are rotated by the action of drawing off a thread therefrom, e.g. with the usual draw 7 .ion during the-thread twisting operation.

r The term thread is employed herein to include various fiber forms including yarns, strings, tows, a monofilament, filament bundles and the like. The fibers may be natural, artificial or synthetic, and the threadxmay'be composed of continuous filaments or staple fibers.

Refe "ng now. to the drawings, FIG. 1 illustrates a double twist twisting machine as a preferred embodiment in combination with the compensating apparatus of the invention. This machine is shown partly in schematic form with certain conventional portions omitted. The machine requires a stationary frame which is provided by spool carrier 1 and various elements connected thereto. The spool carrier 1 is maintained in a stationary position in a conventional manner, e.g. by means of an eccentric weight located on one side of the carrier while inclining the'machine from the vertical position shown. A stationary spool carrier can also be achieved by mounting one or more magnets around thecarrier at a sufficient dis! 'tance therefrom to permit passage of ,the ballooning tread T. These outwardly spaced magnets are placed opposite the othernragnets in or onthe spool carrier itself, and the attraction between opposing magnets holds the carrier in place. Since these means of holding the carrier stationaryhave become quite standard in the art, the drawings have been simplified to avoid illustrating the corresponding elements of the apparatus.

V A hollow spindle 2 extends above the spool carrier 1 'and carries rotatably thereon two separate hollow spoolnormally urged inwardlywith a contact pressure against receiving holders-3 and 4 which fit tightly into two bobbin spools carrying the thread packages 5 and 6. The bobbins or thread'wound spools are wound in such a manner that the spools must rotate on the spindle as the thread is drawn therefrom, and the thread reciprocably traverses the bobbin from one end to the other. Each bobbin 5 and 6 rotates independently on the common axis of the spindle 2 as the individual threads are drawn therefrom.

A stable basket frame is completed by the side supports 7 and 8 connecting the spool carrier 1 to the upper ring 9. Additional supports such as 7 and 8 can be added for greater stability, but for convenience have been omitted from the drawing. On one of the side supports 7 and the upper ring 9, there is connected or mounted in fixed position a series of thread guide elements in the form of eyelets or hooks 10, 11 and 12. Eyelet 10 receives the thread from bobbin 6 and leads and thread therefrom directly above to eyelet 11 which in turn receives the thread from bobbin 5.

During operation of the twisting machine, the threads are drawn off laterally from each bobbin 5 and 6 and conducted in common from eyelet 11 to the third eyelet 12 on upper ring 9 and around the end of the bobbins over the guide roller 13 and into a hollow bore or channel of the spindle 2. The threads are then drawn through the bore of spindle 2 and outwardly through a rotating annular channel or slot and to the thread reserve disc 14, all in the conventional manner of a double twist twisting machine. As the threads emerge from the reserve disc 14, they are lead outwardly in a rotating balloon T arround the end of the bobbins, through eyelet 15, over a preliminary draw-elf roll 16 and onto a take-up reel or draw-off rolls 17 and 18, these rolls representing the point at which drawing or unwinding of the threads from the bobbins originates.

' The compensating apparatus of the invention as shown in FIG. 1 with a double twist twisting machine includes a socket 19 mounted or fixed to the spool carrier 1, and this socket 19 receives the upright shaft or tubular rod 20 inserted rotatably therein. An adjusting ring or collar 21 holds the rod 21 in the socket 19 and can be positioned at various points around the circumference of rod 20 by means of the adjusting screw 22. The torsion spring 23 operates to resiliently urge the rod 20 in a clockwise direction When viewed from above.

At the upper end of rod 20 and approximately perpendicular thereto, there is fixed a swinging arm or shaft 24 adapted to pivotally receive a U-shaped, V-shaped or Y-shaped yoke with two oppositely disposed carrier arms 25 and 26. A pin or yoke handle 27 at the base of the yoke is seated to turn in the swinging arm 24, as more clearly illustrated in FIG. 10. At the free ends of the carrier arms 25 and 26, friction rollers 28 and 29 are independently and rotatably mounted on individual axles 30 and 31. The friction rollers and/or their axles are preferably attached in a removable or interchangeable fashion to the respective carrier arms.

The torsion spring 23 acts through rod 20 to resiliently urge the swinging arm and pivotal yoke handle 27 inwardly toward the bobbins 5 and 6 such that friction rollers 28 and 29 are pressed with a certain con-tact pressure inwardly against or along a circumferential surface area of the two bobbins. The pivotal linkage or pivotal joint formed by yoke handle 27 inserted in the swinging arm 24 assures that the two friction rollers will engage their respective bobbins regardless of minor differences in the diameters of the bobbins. The contact pressure of the two friction rollers is relatively equal and can be adjusted by turning collar 21 to compress or expand the torsion spring 23.

Torque transmission means between the friction rollers 28 and 29 is provided by an endless belt 32 which passes around each roller and is preferably engaged in a groove 33 cut around the circumference of the roller as more fully shown in FIGS. 3 and 4. The endless belt or belt drive 32 is guided from one friction roller to the other by suitable guide means such as rollers 34 as shown in FIGS. 1 and 4 which are rotatably mounted on axles 35. These axles 35 are in turn attached opposite one another and a slot on the carrier arms 25 and 26, for example, byv

engaging the arm 36 in slot 25a as shown in FIG. 16, and securing the arm in place by means of a clamping plate 25b which is tightened by nut 25c.

In FIGS. 1 and 2, the endless belt 32 passes from one friction roller to the other without crossing itself such that these rollers rotate in opposite directions. In this case, the bobbins 5 and 6 are likewise adapted to rotate in opposite directions with respect to each other and with respect to their associated friction rollers. It is more common in double twist twisting machines for both bobbins to rotate in the same direction, and in this case the endless belt 32 must cross itself as indicated in FIGS. 3 and 4 such that the friction rollers will also rotate in the same direction with respect to each other.

In FIGS. 1-4, the belt 32 is entirely engaged or contained within grooves 33 of the friction rollers so that only.

the outer circumferential surface of the friction rollers contacts the outer surface of the bobbins. However, it is.

This latter embodiment is illustrated by way of example in the partial view shown in FIG. 5.

FIG. 6 illustrates a means of individually adjusting the contact pressure of apair of friction rollers bearing against two adjacent bobbins. This construction includes two carrier arms 25 and 26 which are connected at right angles to individually mounted and spring urged shafts 41 and 42. The lower shaft can be mounted on the spool carrier 1 as in FIG. 1 and the upper shaft can be mounted to the upper ring 9 or similar stationary framework. Each torsion spring 43 and 44 can then be individually adjusted by means of a corresponding adjusting collar and screw. The friction rollers, endless belt, and belt guide means otherwise remain the same as illustrated in FIG. 1. The separately adjustable contact pressure is especially useful with a different type of thread on each 'bobbin or in those cases where the bobbins have a slightly different diameter.

All of the elements of the compensating apparatus in are individually mounted for normally independent rota tion. The axle 45 is a relatively flexible rod which is permitted to bend between the two carrier arms 25 and 26 on which the ends of the axle are mounted. The friction rollers are held in position on this flexible axle by means of stops 46 which may be integral with the axle. The flexibility of the axle 45 permits a greater degree of freedom in the movement of the friction rollers so as to accommodate variations in the circumferential surface of the bobbins. nected between the two carrier arms, this construction is not essential since the friction rollers rotate freely-thereon and can instead be carried by individual flexible axles which are not connected. In either case, this construction permits the elimination of the pivotal yoke handle 27 as illustrated in FIG. 10.

7 It is. often desirable to provide a compensation for more than two rollers, and this embodiment of the invention is illustrated by FIG. 7. Where three bobbins 5,

While the axle 45in FIG. 8 is conpensation of the upper bobbins; and 6. This pair of.

' friction rollersis mounted on a common yoke as in FIG.

1, the yoke in turn being pivotally mountediin swinging arm 24 carried at right angles by the spring urged shaft 20. An identical second pair of friction rollers 28 and 29' are also operatively coupled and are driven by belt 32 for compensation of the lowerpair of bobbins 6 and 5', respectively; This second pair of friction rollers is also carried on a common yoke attached to swinging arm 24' carried at right angles by the lower spring urged shaft 20'. In this manner, the center bobbin 6 is operatively coupled by torque transmission means tothe other two bobbins 5 and 5. If one of'the three bobbins tends to run ahead'of or lag behind the other two, the friction rollers coupled in tandem or series will provide an equalization or compensation sufiicient to brake or speed up the unequally rotating bobbin. If desired, bobbins 5 V and 5 may also be coupled by a pair of belt-linked friction rollers, but it is ordinarily sufficient to merely couple' adjacent bobbins 7 The compensating apparatus in FIG. '9 corresponds to that'shown in FIG. 1 except'that the friction rollers 28 and 29 are integral with axles'30' and 31'. Both the friction rollers and their axles rotate freely in their respective carrier armsZS and 26. In addition, the rotating axle 31' extends into a'gear box.47 which is pivotally mounted on shaft so as to swivel together with the swinging arm 24. This gear box'47 is designed as a separate drive for friction roller 29. The drive can be powered by a spring-wound mechanismcontained within the gear box itself, or power can be supplied from an outside source. The power driven gears of gear box 47 should be adapted to be engaged or disengaged from the axle 3 1. This additional drive is especially useful in starting the machine from a standstill, i.e. at the beginning of the thread draw-off, because it is thereby possible to impart a starting torque to the stationary bobbins which will supplement the torque provided by pulling the thread. After reaching the required rate of speed for drawing otf the thread, this supplementary gear drive can be disengaged. The disengagement is preferably made automatic by means of gears remaining in engagement for only a predetermined period of time or by means of suitable mechanism adapted to disengage the gears after the bobbins reach a speed which will overcome their initial inertia.

FIG. 11 discloses an embodiment of the invention in which two bobbins 48 and 49 rotate independently on adjacent spindles 50 and 51. The two spindles are positioned in the same plane at about right angles. Two friction rollers 52 and 53 are mounted for rotation on carrier arms in the form of yokes54 and 55, respectively. These yokes 5'4 and 55' are in turn pivotally connected by means of a suitable yoke handle to a swinging arm adapted to rotate with the respective shafts 56 and 57 in a manner corresponding to that shown in FIG. 1. Torsion springs 58 and 59 act to urge the shafts 56am} 57 in a direction. which will press the friction rollers against their respective bobbins. Thetwo friction rollers 52 and 53 are operatively coupled 'and driven by the endless belt 60 which is guided between the rollers by means of guide pins 61 and 62 adjustably mounted to theguide franie 63.

Thread T is drawn from each of the bobbins as indicated.

by the arrows in FIG. 11, and the thread from each bobbin is joined at eyelet 64, the threads then being drawn oif togetherin a conventional manner.

The belt guide means are more clearly shown in the enlarged views of FIGS. 12 and 13. The guide frame 63' is permanently mounted on a suitable stationary support 65 and includes two arms .66 and 67 joined at their base f and extending in a direction which corresponds to or is in alignment with the path'of the endless belt 60. A continuous slot 68 in the arms '66 and '67 is adapted to receive guide pins 61 and 62 which are adjustablly positioned in the slot by means of wing nuts69 and 70. The guide pins can then be moved in the. slot to providedifferent tensions on the belt which drives the two rollers- As shown in FIG. 13, the endless belt 60'may cross itself in order to provide an opposite rotation of the two friction rollers. In FIG. 11, the belt does not cross itself, andboth friction rollers rotate in the same direction.

The arrangement of FIG. 11 can be adapted to bobbins which rotate on spindles set at various angles to each other. The same type of construction can be usedwith bobbins which rotate on separate spindles in parallel relationship to each other, for example, as illustrated in FIGS. 14 and 15 wherein the various members of the apparatus are designated by the same numbers as in FIGS. 11-13 but are arranged in a slightly different manner to accommodate bobbins 48 and 49 on parallel spindles 50 and 51.

These and other modifications of the invention will be readily apparent to those skilled in the art.

It will be obvious that the friction rollers coupled by a belt drive provide a high degree of versatility in compensating apparatus for the purpose of equalizing the feed rate of two or more feed spools. Regardless of the arrangement of the feed spools or bobbins, friction rollers can be applied thereto in individual pairs or in succeeding pairs so that each bobbin will brake or accelerate adjacent or succeeding bobbins. Equal lengths of thread are thereby drawn off from the individual bobbins so as to provide a uniform product where the threads are joined together to form a single twisted or untwisted yarn. The compensating apparatus of the invention is also advantageous in providing a high degree of adjustment to differ: ent bobbin diameters or diiferent types of threads. An additional feature of the invention is that the compensat ing apparatus can be readily combined with existing equipment for handling two or more feed spools. It will be understood that various modifications in the individual elements of the apparatus or their arrangement with each other can be made without departing from the spirit of the invention or the scope of the appended claims.

The invention is hereby claimed as follows:

.1. An improved compensating device for drawing olf thread from a plurality of bobbins which comprises: spindle means adapted to receive a plurality of bobbins mounted adjacent to each other for normally independent rotation; a stationary framework in proximity to said spindle means and said bobbins; at least one friction roller associated with each of said bobbins, each of said friction rollers being connected to said framework and being separately mounted on its own axle for normally independent rotation; means to resiliently urge each of said friction rollers inwardly in approximately tangential position against an outer circumferential surface of its respective bobbin; means on the outer circumferential surface of each of said rollers for rolling frictional engagement with said outer circumferential surface of its respective bobbin;

and torque transmitting means including a belt drive exand torque transmitting means being arranged to provide rotational compensation of more than two bobbins.

3. An improved compensating device as claimed in claim 1 wherein said bobbins are received on said spindle, 7

means for rotation around a common axis.

4. An improved compensating device as claimed in claim 1 wherein said bobbins are received on said spindle means for rotation around a separate axis for each bobbin.

S. An improved compensating device as claimed in claim 4 wherein said axes are parallel to each other.

6. An improved compensating device as claimed in claim 1 wherein each of said rollers is connected to said framework by a carrying arm pivotally mounted to swing said roller inwardly against its respective bobbin.

7. An improved compensating device as claimed in claim 6 including guide means on. each carrying arm to direct the path of said belt which couples and drives a pair of said rollers.

8. An improved compensating device as claimed in claim 7 wherein said guide means for said belt are adjustably secured to said carrying arms to provide for different tensions on said belt.

9. An improved compensating device as claimed in claim 1 wherein one of the coupled rollers is operatively driven by means separate from said bobbins and other rollers, said separate driving means being adapted to be engaged with said one of the coupled rollers during the initial drawing off of thread from said bobbins with increasing rotational speed thereof and to become disengaged from said one of the coupled rollers thereafter.

10. In a double twist twisting machine having a hollow spindle, means to receive two bobbins in a position adjacent to each other for normally independent rotation around the axis of said spindle, a stationary framework including means to support said spindle and said bobbins, guide means to lead a thread outwardly from each bobbin as said thread unwinds therefrom and to further lead each thread in a path around one end of said bobbins, through said hollow spindle and then outwardly in a rotating balloon around the other end of said bobbins whereby a twist is imparted to said threads, said guide means including a common guide member where said threads are joined prior to twisting, the improvement which comprises: a substantially cylindrical friction roller for each of said bobbins, each of said friction rollers being connected to said framework and being separately mounted on an axle for normally independent rotation;

means to resiliently urge each of said friction rollers inwardly in approximately tangential position against an outer circumferential surface of'its respective bobbin; means on the outer circumferential surface of each of said rollers for frictional rolling engagement with said outer circumferential surface of its respective bobbin; and torque transmitting means including a belt drive extending between and operatively coupling said normally independently rotating friction rollers.

11. A double twist twisting machine as claimed in claim 10 wherein said friction rollers are rotatably mounted on oppositely disposed carrying arms of a common yoke, said yoke being pivotally connected to said framework for reciprocating movement in a direction approximately perpendicular to the axis of said bobbins such that said yoke and said rollers are resiilently urged inwardly against said bobbins with approximately the same force.

12. A double twist twisting machine as claimed in claim 10 wherein each of said friction rollers is rotatably mounted to its own carrying arm, each carrying arm' being separately pivotally connected to said framework for reciprocating movement in a direction approximately perpendicular to the axis of said bobbins, and separate means to resiliently urge each of said carrying arms with its roller inwardly against said bobbins, whereby a different force can be applied by each roller.

References Cited in the file of this patent UNITED STATES PATENTS 

